This project is an in-depth, multidisciplinary study of the biology and biochemistry of mammary cancer in the mouse. Specific research efforts are designed to compare normal, pre-neoplastic and malignant mammary cells and tissues with respect to: 1. The pattern of steroid hormone dependency during the transformation of normal mammary cells to the malignant state. 2. The regulation by prolactin and estradiol-17 on the transcription and transport of specific messenger RNA's. 3. The respective regulatory roles played by cyclic nucleotides. 4. Changes in cell agglutinability or in plasma membrane glycoproteins and glycolipids. 5. The rate and extent of histone and non-histone protein side-group modifications. 6. The metabolism of collagen and related enzyme systems. 7. The relative roles played by polycyclic hydrocarbon epoxidase, epoxide hydrase, aryl hydrocarbon hydroxylase and glutathione-S-epoxide transferase in the susceptibility or resistance to the potential carcinogenic effects of polycyclic hydrocarbons. In addition, a scanning transmission energy analysis electron microscope is being developed to localize hormone and plant lectin binding sites in mammary cells.